1. Field of the Invention
This invention relates to air preheaters and in particular to the modification of modular air preheaters.
2. Description of Related Art
An air preheater (also known as a rotary heat exchanger) is employed to transfer heat from a hot gas stream such as, for example, a flue gas stream, to a cold gas stream such as, for example, combustion air stream. A rotor contains a mass of heat absorbent material which is first positioned in a passageway for the hot gas stream where heat is absorbed by the heat absorbent material. As the rotor turns, the heated absorbent material enters the passageway for the cold gas stream where the heat is transferred from the absorbent material to the cold gas stream.
In a typical air preheater, a cylindrical rotor is disposed on a central rotor post and divided into a plurality of sector-shaped compartments (“sectors”) by a plurality of radial partitions or plates, known as diaphragms, extending from the rotor post to the outer peripheral shell of the rotor. These sector shaped compartments are loaded with modular heat exchange baskets which contain the mass of heat absorbent material commonly comprised of stacked plate-like elements.